[Examples] Add a training script for SDXL DreamBooth LoRA (huggingface#4016)

* add dreambooth lora script for SDXL incorporating latest changes.

* remove use_auth_token=True.

* add: documentation

* remove unneeded cli.

* increase the number of training steps in the readme.

* add LoraLoaderMixin to the subclassing mix.

* add sdxl lora dreambooth test.

* add: inference code sample.

* add: refiner output.

* add LoraLoaderMixin to the mix of classes of StableDiffusionXLImg2ImgPipeline.

* change default resolution of DreamBoothDataset.

* better sdxl report path.

* Apply suggestions from code review

Co-authored-by: Pedro Cuenca <[email protected]>

---------

Co-authored-by: Pedro Cuenca <[email protected]>

Author: sayakpaul

docs/source/en/training/dreambooth.mdx

@@ -701,3 +701,7 @@ accelerate launch train_dreambooth.py \
   --class_labels_conditioning timesteps \
   --push_to_hub
 ```
+
+## Stable Diffusion XL
+
+We support fine-tuning of the UNet shipped in [Stable Diffusion XL](https://huggingface.co/papers/2307.01952) with DreamBooth and LoRA via the `train_dreambooth_lora_sdxl.py` script. Please refer to the docs [here](https://github.com/huggingface/diffusers/blob/main/examples/dreambooth/README_sdxl.md). 

examples/dreambooth/README.md

@@ -737,3 +737,7 @@ accelerate launch train_dreambooth.py \
   --class_labels_conditioning timesteps \
   --push_to_hub
 ```
+
+## Stable Diffusion XL
+
+We support fine-tuning of the UNet shipped in [Stable Diffusion XL](https://huggingface.co/papers/2307.01952) with DreamBooth and LoRA via the `train_dreambooth_lora_sdxl.py` script. Please refer to the docs [here](./README_sdxl.md). 

examples/dreambooth/README_sdxl.md

@@ -0,0 +1,178 @@
+# DreamBooth training example for Stable Diffusion XL (SDXL)
+
+[DreamBooth](https://arxiv.org/abs/2208.12242) is a method to personalize text2image models like stable diffusion given just a few (3~5) images of a subject.
+
+The `train_dreambooth_lora_sdxl.py` script shows how to implement the training procedure and adapt it for [Stable Diffusion XL](https://huggingface.co/papers/2307.01952).
+
+> 💡 **Note**: For now, we only allow DreamBooth fine-tuning of the SDXL UNet via LoRA. LoRA is a parameter-efficient fine-tuning technique introduced in [LoRA: Low-Rank Adaptation of Large Language Models](https://arxiv.org/abs/2106.09685) by *Edward J. Hu, Yelong Shen, Phillip Wallis, Zeyuan Allen-Zhu, Yuanzhi Li, Shean Wang, Lu Wang, Weizhu Chen*. 
+
+## Running locally with PyTorch
+
+### Installing the dependencies
+
+Before running the scripts, make sure to install the library's training dependencies:
+
+**Important**
+
+To make sure you can successfully run the latest versions of the example scripts, we highly recommend **installing from source** and keeping the install up to date as we update the example scripts frequently and install some example-specific requirements. To do this, execute the following steps in a new virtual environment:
+
+```bash
+git clone https://github.com/huggingface/diffusers
+cd diffusers
+pip install -e .
+```
+
+Then cd in the `examples/dreambooth` folder and run
+```bash
+pip install -r requirements_sdxl.txt
+```
+
+And initialize an [🤗Accelerate](https://github.com/huggingface/accelerate/) environment with:
+
+```bash
+accelerate config
+```
+
+Or for a default accelerate configuration without answering questions about your environment
+
+```bash
+accelerate config default
+```
+
+Or if your environment doesn't support an interactive shell (e.g., a notebook)
+
+```python
+from accelerate.utils import write_basic_config
+write_basic_config()
+```
+
+When running `accelerate config`, if we specify torch compile mode to True there can be dramatic speedups. 
+
+### Dog toy example
+
+Now let's get our dataset. For this example we will use some dog images: https://huggingface.co/datasets/diffusers/dog-example.
+
+Let's first download it locally:
+
+```python
+from huggingface_hub import snapshot_download
+
+local_dir = "./dog"
+snapshot_download(
+    "diffusers/dog-example",
+    local_dir=local_dir, repo_type="dataset",
+    ignore_patterns=".gitattributes",
+)
+```
+
+Since SDXL 0.9 weights are gated, we need to be authenticated to be able to use them. So, let's run:
+
+```bash
+huggingface-cli login
+```
+
+This will also allow us to push the trained LoRA parameters to the Hugging Face Hub platform. 
+
+Now, we can launch training using:
+
+```bash
+export MODEL_NAME="diffusers/stable-diffusion-xl-base-0.9"
+export INSTANCE_DIR="dog"
+export OUTPUT_DIR="lora-trained-xl"
+
+accelerate launch train_dreambooth_lora_sdxl.py \
+  --pretrained_model_name_or_path=$MODEL_NAME  \
+  --instance_data_dir=$INSTANCE_DIR \
+  --output_dir=$OUTPUT_DIR \
+  --mixed_precision="fp16" \
+  --instance_prompt="a photo of sks dog" \
+  --resolution=1024 \
+  --train_batch_size=1 \
+  --gradient_accumulation_steps=4 \
+  --learning_rate=1e-4 \
+  --report_to="wandb" \
+  --lr_scheduler="constant" \
+  --lr_warmup_steps=0 \
+  --max_train_steps=500 \
+  --validation_prompt="A photo of sks dog in a bucket" \
+  --validation_epochs=25 \
+  --seed="0" \
+  --push_to_hub
+```
+
+To better track our training experiments, we're using the following flags in the command above:
+
+* `report_to="wandb` will ensure the training runs are tracked on Weights and Biases. To use it, be sure to install `wandb` with `pip install wandb`.
+* `validation_prompt` and `validation_epochs` to allow the script to do a few validation inference runs. This allows us to qualitatively check if the training is progressing as expected. 
+
+Our experiments were conducted on a single 40GB A100 GPU.
+
+### Inference
+
+Once training is done, we can perform inference like so:
+
+```python
+from huggingface_hub.repocard import RepoCard
+from diffusers import DiffusionPipeline
+import torch
+
+lora_model_id = <"lora-sdxl-dreambooth-id">
+card = RepoCard.load(lora_model_id)
+base_model_id = card.data.to_dict()["base_model"]
+
+pipe = DiffusionPipeline.from_pretrained(base_model_id, torch_dtype=torch.float16)
+pipe = pipe.to("cuda")
+pipe.load_lora_weights(lora_model_id)
+image = pipe("A picture of a sks dog in a bucket", num_inference_steps=25).images[0]
+image.save("sks_dog.png")
+```
+
+We can further refine the outputs with the [Refiner](https://huggingface.co/stabilityai/stable-diffusion-xl-refiner-0.9):
+
+```python
+from huggingface_hub.repocard import RepoCard
+from diffusers import DiffusionPipeline, StableDiffusionXLImg2ImgPipeline
+import torch
+
+lora_model_id = <"lora-sdxl-dreambooth-id">
+card = RepoCard.load(lora_model_id)
+base_model_id = card.data.to_dict()["base_model"]
+
+# Load the base pipeline and load the LoRA parameters into it. 
+pipe = DiffusionPipeline.from_pretrained(base_model_id, torch_dtype=torch.float16)
+pipe = pipe.to("cuda")
+pipe.load_lora_weights(lora_model_id)
+
+# Load the refiner.
+refiner = StableDiffusionXLImg2ImgPipeline.from_pretrained(
+    "stabilityai/stable-diffusion-xl-refiner-0.9", torch_dtype=torch.float16, use_safetensors=True, variant="fp16"
+)
+refiner.to("cuda")
+
+prompt = "A picture of a sks dog in a bucket"
+generator = torch.Generator("cuda").manual_seed(0)
+
+# Run inference.
+image = pipe(prompt=prompt, output_type="latent", generator=generator).images[0]
+image = refiner(prompt=prompt, image=image[None, :], generator=generator).images[0]
+image.save("refined_sks_dog.png")
+```
+
+Here's a side-by-side comparison of the with and without Refiner pipeline outputs:
+
+| Without Refiner | With Refiner |
+|---|---|
+| ![](https://huggingface.co/datasets/diffusers/docs-images/resolve/main/sd_xl/sks_dog.png) | ![](https://huggingface.co/datasets/diffusers/docs-images/resolve/main/sd_xl/refined_sks_dog.png) |
+
+## Notes
+
+In our experiments we found that SDXL yields very good initial results using the default settings of the script. We didn't explore further hyper-parameter tuning experiments, but we do encourage the community to explore this avenue further and share their results with us 🤗
+
+## Results
+
+You can explore the results from a couple of our internal experiments by checking out this link: [https://wandb.ai/sayakpaul/dreambooth-lora-sd-xl](https://wandb.ai/sayakpaul/dreambooth-lora-sd-xl). Specifically, we used the same script with the exact same hyperparameters on the following datasets:
+
+* [Dogs](https://huggingface.co/datasets/diffusers/dog-example)
+* [Starbucks logo](https://huggingface.co/datasets/diffusers/starbucks-example)
+* [Mr. Potato Head](https://huggingface.co/datasets/diffusers/potato-head-example)
+* [Keramer face](https://huggingface.co/datasets/diffusers/keramer-face-example)

examples/dreambooth/requirements_sdxl.txt

@@ -0,0 +1,7 @@
+accelerate>=0.16.0
+torchvision
+transformers>=4.25.1
+ftfy
+tensorboard
+Jinja2
+invisible-watermark>=2.0